The present invention generally relates to medical instruments, in particular such medical instruments which may be coupled with an endoscope.
Medical instruments on which an endoscope is mounted in a displaceable manner are known, for example, from documents DE 40 42 102 C2 or EP 0 117 894 A2.
A large number of medical instruments have been developed to keep pace with the increasing application of minimally invasive surgery. In minimally invasive surgery, operations are performed only through a very small incision in the human body.
An operation performed in a minimally invasive manner is monitored using one or more endoscopes which are advanced to the operating site in the body via the same opening or another opening.
However, the use of a medical instrument and of an endoscope independent of the latter has the disadvantage that the relative position of the endoscope with respect to the instrument changes when one of them moves, thus also changing the view afforded to the operating surgeon. This is tiring for the operating surgeon, especially when performing complicated procedures.
Moreover, since an operation is generally not monitored in the form of a stereo image, the relative position of the endoscope with respect to the instrument and of the instrument with respect to the operating site can often be assessed only with difficulty.
Furthermore, the use of a medical instrument and of an endoscope independent of the latter makes it difficult for operations to be performed by just one person, since at least one assistant is normally needed to guide the endoscope.
For this reason, medical systems have been developed which comprise a medical instrument to which an endoscope is coupled.
Such a system is described in document U.S. Pat. No. 4,759,348, for example. In the system described in this document, the distal end of a flexible endoscope is secured at the distal end of a medical instrument. The system is distinguished by great mechanical simplicity. Moreover, the endoscope can be designed such that it can be fitted on any desired medical instrument.
However, the endoscope is secured only at the distal end of the shaft, which results in a significant increase in the instrument diameter. This makes insertion of the medical instrument into the body much more difficult.
Moreover, in the event of a movement of the movable parts of the medical instrument, this known endoscope does not automatically follow the movement. If the medical instrument therefore has a work element which is displaceable along the longitudinal axis relative to the instrument shaft, the endoscope is not displaced too. This means that the view of the work element afforded to the operating surgeon changes as the work element moves. This in turn makes precise use of the work element difficult.
The document U.S. Pat. No. 5,667,472 describes a similar system in which optical fibers are routed along the whole shaft of the medical instrument. In this way, the instrument diameter is increased barely perceptibly, and both the insertion and also the maneuvering of the instrument during the operation are made much easier.
In this medical system too, however, the endoscope does not follow the movement of the work element of the medical instrument, and this leads to the problems described above.
Document DE 40 42 102 C2 describes a medical instrument into which an endoscope is integrated. The endoscope is in this case operatively connected to the work element of the medical instrument and is displaced in synchrony with the displacement of the work element. The shaft of the endoscope in this case lies in the inside of the shaft of the instrument. The eyepiece of the endoscope is arranged at the proximal end of the instrument, such that the longitudinal axis of the eyepiece coincides with the shaft axis of the instrument.
However, this system has the disadvantage that the endoscope is an integral component part of the medical instrument. Therefore, for each new medical instrument, an endoscope also has to be procured.
Integrating the endoscope into the medical instrument also makes it difficult to dismantle for cleaning and sterilizing purposes. Moreover, this construction proves unsuitable for many HF surgical instruments.
Since, in HF instruments, the work element and the associated conductors for the HF voltage regularly have to be removed for replacement or for sterilization, these are generally designed as straight wires with tools at the distal end. The wires can be introduced from the distal end into the shaft and are secured at the proximal end with a clip contact. Also arranged at the proximal end is the connector for the external feed line of the HF voltage. In HF instruments of this kind, therefore, the space for arranging an endoscope optical system is greatly restricted at the proximal end.
Document EP 0 117 894 A2 describes an instrument similar to the one described in DE 40 42 102 C2. The main difference is that the endoscope is guided inside a medical grasping instrument.